This invention relates to fluorescent lamp crushers, and more particularly to crushers of the type that are designed to crush fluorescent lamp tubes of various lengths and shapes. Even more particularly this invention relates to improved control apparatus for automatically sensing the overall length of each tube inserted into the crusher, and for simultaneously counting incremental lengths of the tubes inserted into the crusher.
Fluorescent tubes or lamps of the type described frequently are marketed in two different shapes--namely, straight or linear, and curved or U-shaped in configuration. Moreover, such tubes normally are marketed in three different lengths--namely, four feet long or eight feet long for the linear or straight tubes, and two feet overall for the U-shaped tubes. The straight tubes which are eight feet in length contain twice as much glass and mercury vapor as each of the straight four foot tubes and U-shaped tubes. Typically tubes of the type described are crushed in fluorescent apparatus of the type disclosed in the U.S. Pat. No. 4,655,404, wherein any toxic mercury vapors, which are released upon the crushing of such tubes, are drawn into and absorbed by a special filter that which is associated with such apparatus.
However, it has been found necessary periodically to change the filter element in crushers of the type noted above, because after prolonged use the filter element becomes saturated and thereafter fails to function properly. For that reason, as noted in the U.S. Pat. No. 5,205,497, it has been customary to employ in connection with such crushers a safety device which prevents further operation of the crusher after a predetermined successive number of lamps have been crushed. In that prior art control apparatus the feed tube, which guides the fluorescent lamp tubes into the crusher, contains a normally-open switch that is closed each time a new tube is inserted into the crusher. The intermittently operated switch operates a counter, which after a predetermined number of counts have been made, interrupts the operation of the crusher until the filter element is replaced. However, this mechanism result in to inaccurate counting, because of the breaking of some fluorescent tubes upon movement of the tubes into the machine feed chute. The effect of such breaking is to create multiple operation of the normally-open switch employed to count the number of tubes inserted into the machine, and therefore frequently has led to an excessive count, and premature replacement of the filter element.
To obviate the foregoing problem, crusher machines have been equipped heretofore with a manually-operated tube size selector switch, which the machine operator actuated at the time the tube was inserted into the crusher machine to indicate whether the tube was a four foot tube, an eight foot tube or a U-shaped tube. If the operator properly operated the tube size selector switch, the mechanism produced an accurate account representing the volume of the crushed tubes, and consequently an accurate representation of the crushed glass and mercury vapor released per tube. However, the accuracy depended upon the conscientious operation of the tube size selector switch, and if the machine operator failed properly to operate the selector, then the count was inaccurate. Moreover, this created the possiblity that the operator could deliberately fail to make the correct tube size selection for the purpose of prolonging the useful life of the associated filter element, in which case the element very often could be operated after reaching its saturation point.
It is an object of this invention, therefore, to provide an improved control apparatus for crushers of the type described, which will provide a far more accurate measure of the crushed glass and vapor created by the crusher subsequent to the insertion of the filter element therein, and which will prevent any deliberate operation of the crusher after its associated filter element has become saturated.
A more specific object of this invention is to provide improved crusher apparatus of the type described which, in effect, automatically and accurately senses the type of fluorescent tube which is inserted into the machine, and which, regardless of the size and shape of the tube inserted, provides an accurate count for each predetermined quantity of crushed glass and mercury vapor released into the crusher.
Still another object of this invention is to provide for fluorescent lamp crushers of the type described improved control apparatus which includes means for automatically sensing the insertion of long and short tubes into the crusher, including U-shaped tubes, and which prevents any multiple or accidental triggering thereof.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.